Help with planning a ventilation system

A garage does not have any ventilation openings at all

In normal garages there are ventilation openings and that is sufficient there. I would try to retrofit something like that (core drilling, grilles). The planned construction is, IMHO, oversized (like using a cannon to kill a sparrow ...).

Thank you very much for the answers, the decision has now been made in favor of a computer-controlled ventilation system including data recording.

The air flow has changed so far that the exhaust air is blown directly from the garage to the outside.

Three fans will be installed, one that sucks the fresh air from outside into the workshop, one that blows from the workshop into the garage, and another that directs the exhaust air from the garage to the outside.

Five sensors will be installed, one that measures the intake air, one that determines the airflow between the workshop and the garage, one that measures the exhaust air, and one each in the garage and in the workshop that measure the room humidity.

The relative humidity and temperature are measured each time and from that the absolute humidity is determined.

The control system then decides between ventilation and dehumidification.

I am just not yet sure how to select and size the fans.

In the two wall openings I would like to use rotary fans.

How much throughput should each fan provide, considering that now three fans are connected in series?

Best regards Manuel

Normally, 0.5 * room volume per hour would probably be enough. But for you, rather factor 10, because of safety ;-). *SCNR*

With us, everything is a bit more elaborate, we also shoot our sparrows with an old 8.8 :D

Joking aside, the whole thing sounds more elaborate and expensive than it actually is,
the control runs via a Raspberry Pi, sensors and relays together cost about €20 and I get the rest at dealer prices.
Everything together will cost about €200.
Of course, fun and learning success will not be neglected either.